1. Field of the Invention
This invention relates to drying granular or powdery material, preferably granular resin material, prior to processing thereof into intermediate or finished products, preferably by extrusion or molding.
2. Description of the Prior Art
It is known to dry granular resin material by placing the granular resin material pellets on large shallow trays to a depth of one or two inches, and putting those trays into ovens for several hours. With this approach to granular resin material drying, drying temperatures of up to 150-180° F., but no higher, can be used since many granular resin materials begin to soften at 200-210° F.
The apparatus and method of U.S. Pat. No. 6,154,980 represent a substantial improvement over and a radical departure from known desiccant dryer technology by providing methods and apparatus which substantially accelerate the drying process, providing greater throughput of dried granular resin material at lower cost than previously known or achievable. The method and apparatus disclosed in pending U.S. patent application Ser. No. 09/883,837, published as U.S. patent publication 2002-0024162-A1, provide further improvement over the methods and apparatus disclosed in U.S. Pat. No. 6,154,980, particularly in the evacuation of the granular material, once dried, from the drying apparatus.